Universal ring jaws

ABSTRACT

The invention describes apparatus for chucking work in lathes. A pie-shaped, segmented, planar backing plate is attached to a lathe in such a manner as to permit radial movement without affecting the planar orientation of each of the segments. A plurality of segments constituting a ring are attached to the backing plate. This ring is machined to accept the work piece in either an inside diameter or outside diameter relationship. After the work piece is mounted onto the segmented ring, the segments of the backing plate are moved radially inwardly or outwardly, depending on the method of attaching the work piece, to snugly hold the work piece during the machining operation of the work piece. The size of the backing plate is constricted only by the peripheral equipment about the lathe and is not related to the size of the lathe chuck jaws themselves. Similarly, the size of the segmented ring employed with the backing plate is determined by the inside or outside diameter of the portion of the work piece used in securing the work piece to the segmented ring.

United States Patent 1 Bailiff July 24, 1973 UNIVERSAL RING JAWS [76]Inventor: Vernon Brooks Bailiff, 3608 W.

Harmont Dr., Phoenix, Ariz. 85021 22 Filed: Oct. 4, 1971 21 Appl. No.:185,972

[52] US. Cl 279/1 SJ, 279/110, 279/123,

[51] Int. Cl B23b 31/10 [58] Field of Search 279/1 SJ, 110, 123

[56] References Cited FOREIGN PATENTS 0R APPLICATIONS 104,488 3/1917Great Britain 279/123 Primary ExuminerFrancis S. I-Iu sarAttorney-William C. Cahill et al.

[57] ABSTRACT The invention describes apparatus for chucking work inlathes. A pie-shaped, segmented, planar backing plate is attached to alathe in such a manner as to permit radial movement without affectingthe planar orientation of each of the segments. A plurality of segmentsconstituting a ring are attached to the backing plate. This ring ismachined to accept the work piece in either an inside diameter oroutside diameter relationship. After the work piece is mounted onto thesegmented ring, the segments of the backing plate are moved radiallyinwardly or outwardly, depending on the method of attaching the workpiece, to snugly hold the work piece during the machining operation ofthe work piece. The size of the backing plate is constricted only by theperipheral equipment about the lathe and is not related to the size ofthe lathe chuck'jaws themselves, Similarly, the size of the segmentedring employed with the backing plate is determined by the inside oroutside diameter of the portion of the work piece used in securing thework piece to the segmented ring.

6 Claims, 5 Drawing Figures FATE NIH; JUL 3. 747. 945

SHEET 1 [IF 2 UNIVERSAL RING JAWS This invention relates to devicesuseful in expansively or contractively attaching work pieces to lathes.

In the prior art, various methods have been used to attach work piecesto lathes. Initially, a slit collet was used to directly hold the workpiece and on occasion it had to be machined to fit. This machiningoperation was expensive as the collets were of hardened material. Oncemachined, the collets were adapted to fit only work pieces of thatparticular diameter, unless further enlarged. After the collets had beenmachined to the point where the metal remaining in the periphery wasinsufficient to form the chucking jaws for the work piece, the colletshad to be discarded. The attendant replacement costs further increasedthe costs of the machining operation.

To overcome the above-described collet machining and replacement costs,pie-shaped chuck jaws of soft material, such as aluminum were boltedonto the respective slit portions of the collet. With thisconfiguration, the aluminum chuck jaws, rather than the collet, weremachined to fit and hold the work piece. This method saved the cost ofmachining the hardened collets and their replacement, but introducedfurther and different problems. The aluminum chuck jaws were of uniformthickness from their center to their periphery. To hold a work piece,the chuck jaws had to be machined either from the center outwardly orfrom the periphery inwardly, depending on whether the work piece was tobe held by expanding against an inside diameter or contracting againstan outside diameter of the work piece. As with the prior machining ofthe collets, once the chuck jaws have been machined, further utility waspredicated on future work pieces being of lesser or greater diameter,depending on whether the work piece is held contractively orexpansively. In many situations, the machining operation in preparingthe chuck jaws removed a large portion of the material and thus severelylimited its future usefulness. For dish-shaped work pieces, where thedished portion is to be imbedded within the chuck jaws, a large amountof material at the center of the chuck jaws must be removed. The settingup time required for so preparing the chuck jaws is expensive and limitsthe future usefulness of the chuck jaws.

In situations requiring the machining of hard work pieces, such asHastalloy or Waspalloy, the chuck jaws must be tightened to agreater-than-normal extent to retain the work piece on the chuck jaws ina non-sliding relationship. This additional tightening will tend to bendor'distort the aluminum chuck jaws due to the leverage arm between thecollet attachment and the point of attaching the work piece. Distortionof the chuck jaws in a plane normal to the axis will also misalign thegroove or shoulder machined into the chuck jaws for securing the workpiece. Misalignment of the groove or shoulder will cause the work piecenot to seat properly. This result is wholly unacceptable in situationsrequiring close tolerance work.

The use of soft aluminum chuck jaws secured between a collet and thework piece presents a still further problem. The axial distance betweenthe collet member and the point of contact between the work piece andthe cutting tool may be great enough to permit the aluminum chuck jawsto bend or distort under pressure of the cutting tool. This problembecomes more prevalent as the chuck jaws become thinned after repeatedmachining. Any distortion caused thereby will effect the accuracy withwhich the work piece may be machined.

It is therefore a primary object of the present invention to provide arigid support for machining work pieces.

Another object of the present invention is to provide an easilymachinable segmented ring jaw for supporting a work piece.

Another object of the present invention is to provide a segmented ringjaw requiring a minimum amount of machining to attach a work piecethereto.

Another object of the present invention is to provide a planarly rigidbacking plate for supporting segmented ring jaws.

Still another object of the present invention is to provide a pluralityof different sized segmented ring jaws attachable to a single planarbacking plate.

These and other objects of the present invention will become apparent tothose skilled in the art as the description thereof proceeds.

The present invention may be described with more specificity and claritywith reference to the following figures, in which:

FIG. 1 illustrates a lathe incorporating the teachings of the presentinvention.

FIG. 2 illustrates a cross-sectional .view of the present invention.

FIG. 3 illustrates the backing plate of the present invention.

FIG. 4 illustrates a cross section of the backing plate shown in FIG. 3.

FIG. 5 illustrates a pair of different sized ring jaws of the presentinvention.

Referring to FIG. 1, there is shown a lathe housing 1 having a lathechuck 2 extending therefrom. Conventional lathes and lathe chucks arewell understood in the art and the following description will only touchupon those aspects directly co-operating with the present invention. Thelathe chuck 2 has a plurality of jaw mountings 3 extending radially andmovable radially toward and away from the axis of rotation of the lathechuck 2. The radial inward and outward movement of the jaw mountings 3is controlled by a gearing mechanism which is substantially conventionalin all lathe chucks 2 and is controlled by a hand wrench fitting in thewrench receiving socket 4.

In the preferred embodiment of the invention, the backing plate 5 isconstructed of three segregable pieshaped planar members 5a, 5b, and 50.Each of the members 5a, 5b, and 5c includes a plurality of holesgenerally radially oriented with respect to each other and generallycentered between the radial edges of the member. Each of the membersincludes an integral assembly 6 which interfaces with the respective jawmounting in a tongue and groove relationship. Two

.holes 13, 14 in member 5a are aligned with two threaded holes l7, 18within jaw mounting 3. Bolts 19, 20 are countersunk in holes l3, l4 andextend therethrough, and are screwed into holes 17, 18 of jaw mounting 3to firmly secure each member (5a, 5b, 50) to its respective jaw mounting3. In addition, a key 7 of hardened material is attached by bolt 8 tothe respective member in a channel 9 of assembly 6 and engages channel10 in jaw mounting 3 to provide not only a friction fit by tighteningbolts 19 and 20 but also interlocking physical constraints to preventany lateral or rotational movement of piece with respect to jaw mounting3.

Each of the members (5a, 5b, 5c) of backing plate 5 is attachable to theadjacent member through a planar slotted rectangular guide 21, 22, 23.These guides 21, 22, 23 are attached to their respective member 5a, 5b,5c by bolts, such as bolts 37, 38 extending through the slotted portionand threaded into holes, such as holes 39, 40, in the member. Thesurface of each member 5a, 5b, 50 adjacent the guide 21, 22, 23 isplanar with the guide to provide a firm seating. Thus, on tightening therespective bolts to secure the guides 21, 22, 23 to their respectivemembers 511, 5b, 5c, a rigid unitary planar structure is formed. Byloosening the bolts, the members 5a, 5b, 50 may be moved. radially asthe slots 24, 25, 26 of the guides 21, 22, 23 compensate for the changein circumferential distance between the bolts of adjacent members 5a,5b, 50. Thus, the members may be moved radially inwardly until the sidesof the members contact one another and radially outwardly to the extentpermitted by the slots 24, 25, 26 in the guides 21, 22, 23. At theseextremes, or at any point therebetween, the bolts may be tightened tosecure the guides 21, 22, 23 with their respective members and establisha rigid unitary structure. The use of high strength steel for thecomponents of the backing plate 5 and the guides 21, 22, 23 further addsto the rigidity of the unitary structure. If desired, the guides 21, 22,23 may be keyed to their respective members 5a, Sb, 50 by a tongue andgroove arrangement (not shown). With this arrangement, the members 5a,5b, and 5c will be forced to move radially by equal amounts and it willaugment the action of the jaw mountings 3.

In FIGS. 1, 2, and 5, there are shown various views of the ring jaws 27to be used with the backing plate 5. The ring jaws 27 may bemanufactured from aluminum or other easily machinable metal. If desired,they may be manufactured as segments 28, 29, 30 (see FIG. 5) of a ringor as a ring subsequently divided into segments. The width, depth, andradii of the ring jaws 27 may be varied, although the segments may bemost useful if they have a radial cross section of generally rectangularshape. FIG. 5 illustrates two differently sized ring jaws that may bemounted on backing plate 5. Each of the members 5a, 5b, and 50 hasdisposed therein at least two threaded holes 31, 32, each disposed alongand centered on an imaginary circle of lesser diameter than the diameterof the backing plate 5. Similarly, a segmented ring jaw 27, having amean radius equal to the radius of the imaginary circle, has disposedtherein a plurality of holes 33, 34 centered on the imaginary circle andaligned with the threaded holes (such as 31, 32) in the backing plate 5.Each of the segments 28, 29, 30 of the ring jaw 27 is affixed to one ofthe members 5a, 5b, 5c of the backing plate 5 by bolts (such as 35, 36)inserted into the holes 33, 34 in the segment 28 and engaging therespective threaded hole (such as 31, 32) in the respective member. Inthis manner, the segmented ring jaw 27 is attached to the backing plate5. For best results, the bolts 35, 36 should be countersunk in thesegments and the shafts of the bolts should be in close tolerance withtheir respective holes to provide a physical as well as a frictionalconstraint against movement therebetween.

In order to provide a plurality of different sized ring jaws 27 as shownin FIG. 5 for a backing plate 5, a plurality of sets of holes centeredon a plurality of different diametered imaginary circles may be disposedin the backing plate 5. Each of these sets of holes would correspondwith the holes in a plurality of different diametered ring jaws 27.Thereby, only one backing plate 5 would be needed to mount any segmentedring jaw 27 from a size equivalent in diameter to the inward point ofthe backing plate members to a size equivalent in diameter to thecircumference of the backing plate.

The overall functional aspect of the above-described ring jaws 27 issimilar to the functions obtained from the prior art chuck jaws in termsof their role in holding the work piece to be machined. However, thereare a myriad of advantages to be obtained from the ring jaws 27 thatwere not available from the devices of the prior art. Theseadvantageswill become obvious from the following discussion of theoperation of the instant invention.

An advantage of the invention is that of the feasibility with which theinvention may be used on any sized lathe from the smallest to thelargest. The diametrical size of the work piece to be worked on a latheis limited only by the size of the backing plate 5 that can be mountedon the chuck mountings 3. The size of the backing plate 5 is limited bythe lathe structure radially closest to the axis of rotation and whichwould interfere with the rotation of the backing plate 5. Once thelargest possible size backing plate 5 has been determined, it may bemounted on the jaw mountings 3. As it represents the largest size workpiece that can be machined on that particular lathe, there is no need toever remove it, except for reasons of maintenance. This represents asubstantial time and labor savings over prior known chuck jaws as thelatter were continually being used up in terms of continually adaptingthem to receive new different sized work pieces. An ancillary advantageof the invention is that of extending the life of the mechanism securingthe backing plate 5, formerly the chuck jaws, to the rotating shaft ofthe lathe as they must be loosened and tightened less often.

After a backing plate 5 has been selected and mounted on mountings 3, asegmented ring jaw 27 is selected to be attached thereto. The selectionof the size of the ring jaw 27 should be controlled by the followingcriteria. The ring jaw 27 should be selected so that either its insideor outside diameter most closely approaches the diameter of the workpiece portion which is to be mounted thereon. In this manner, the leastamount of material needs to be removed from the ring jaw 27 in preparingit to accept the work piece. This presents a substantial setting up timesavings and a substantial economy in discarded material costs.

Afer selecting the appropriate sized ring jaw 27, each segment 28, 29,30 is mounted on a backing plate member 51:, 5b, 5c and secured theretoby bolts, such as 35, 36. The ring jaw 27 is then machined to providethe requisite seating for the work piece. On completion thereof, theguides 21, 22, 23 are loosened and the backing plate members 5a, 5b, 5care drawn inwardly slightly or extended outwardly slightly, depending onwhether the work piece is fitted onto the ring jaws in an inside oroutside diameter configuration by turning socket 4. This permits thework piece to be fitted onto the ring jaw 27. The work piece is thensecured to the ring jaw 27 by reversely moving the backing plate members5a, 5b, 5c until a snug fit is obtained between the ring jaw 27 and thework piece. The guides 21, 22,

move the work piece, the guides 21, 22, 23 are loosened and the members5a, 5b, and 5c are moved radially to disengage the ring jaw 27 from thework piece.

in situations where the work piece is of very hard and difficult tomachine metal, the radial force exerted by the jaws securing the workpiece has to be substantial to provide the requisite frictional forcetoprevent the work piece from rotating under the forces of the cuttingtool. This situation establishes substantial counter forces that areaxially displaced, causing possible deformation of the jaws, such as thealuminum pie jaws used in the prior art. Any such deformation willmisalign the seating machined in the jaws and subject the work piece touneven forces. Accurate high tolerance of the work piece is thenimpossible. The problem became even more severe after the pie-shapedchuck jaws were thinned due to repeated machining to fit various sizedwork pieces thereon.

in the present invention, the above-described distortion is avoided forall practical purposes. The design of the backing plate 5 is such thatit may be made of high strength steel and by use of the guides 21, 22,23 presents a rigid planar unitary structure not subject to deformationunder any expected loads. The ring jaws 27, though usually made fromaluminum and less rigid than steel, are securely fastened to the backingplate members 5a, 5b, 5c. The steel bolts 35, 36, being in closetolerance with the holes 33, 34 in the segments 28, 29, 30, lendsrigidity to the jaw 27. The axial distance between the heads of thebolts and the work piece is very small and thus presents a minimumleverage arm through which the previously discussed counter forces mayact. Thus, the possibility of the ring jaw 27 securing the work piece toa lathe, as described in the instant invention, being subjected todistortion is at a minimum. To reduce the possibility to practicallyzero for even ultrahard work pieces, the ring jaw, 27 may be made ofsteel rather than aluminum. For extended runs, two sets of ring jawsarranged in an overlapping relationship may be used. Fantastic rigidityis obtained thereby, yet only one set of ring jaws need to be machinedand the second set may be used for other machining operations later on.The expense of machining steel ring jaws is also avoided.

ln many applications, dish-shaped work pieces must be machined. Theinstant invention admirably lends itself to this situation. Here, a ringjaw size is selected which will engage the periphery of the work pieceat or close to the ringjaw 27 inner diameter. Thus, the set-up timepreviously required to machine out pie-shaped jaws to provide a recessfor the dished portion is completely obviated. This represents asubstantial savings in the cost of the machinists time, lathe time, andaluminum.

in some machining operations, there is a requirement to work a flange atthe inner diameter of the work piece. In the previously used pie-shapedaluminum chuck jaws, the jaws had to be machined to provide a recess topermit the cutting tool to, be inserted therein before the work piececould be machined. This operation was a substantial portion of theset-up time re quired and added to the overall cost of the machiningprocess. With the instant invention, the above-required set-up time iswholly avoided as the ring jaw 27 automatically provides a sufficientrecess to insert a cutting tool therein.

The cost of either pie-shaped chuck jaws or ring jaws is basically on adollar per pound basis. Obviously, the less weight that must be machinedaway to fit a work piece onto the jaws the lower is the cost of themachining operation. With the use of the ring jaw 27, the excessmaterial that must be machined away is at a minimum and substantiallyreduces the costs of any machining operation. In example, the costcomparisons obtained over a period of time have been in the neighborhoodof ten to one.

I claim:

1. Apparatus for mounting a work piece on a lathe, which lathe includesa self-centering chuck and chuck jaws, said apparatus comprising incombination:

a. a multimembered planar backing plate;

b. attachment means for attaching one side of each member of said plateto one of the chuck jaws;

lock means for selectively securing adjacent ones of said members in arigid planar relationship with respect to one another, said lock meansbeing positioned radially external to the perimeter of the chuck; j

. a segmented ring having a plurality of arcuate segments, each of saidsegments being anchored to another side of one of said members to formsaid segmented ring; and

. receiving means disposed on each of said segments for engaging aportion of the work piece; whereby the work piece, positioned withinsaid receiving means, is secured to the lathe by radially displacing thechuck jaws to draw said receiving means firmly against the work piece.

2. The apparatus as claimed in claim 1, wherein said multimemberedplanar backing plate comprises three pie-shaped members.

3. The apparatus as claimed in claim 2, wherein said lock meanscomprises a slotted rectangular piece and at least one pair of boltsextending through the slot, each bolt of said pair threadedly engaging adifferent one of adjacent ones of said members, whereby on tighteningsaid bolts said adjacent members are rigidly displaced with respect toone another by said slotted piece.

4. The apparatus as claimed in claim 2, wherein said segmented ringcomprises three segments, each one of said segments extending arcuatelyto either radial edge of the member to which it is attached.

5. The apparatus as claimed in claim I, wherein each of said members arenon-movably attached to its respective chuck jaw by bolts and each ofsaid segments is non-movably attached to its respective member by bolts.

6. The apparatus as claimed in claim 3, wherein said lock means ispositioned in proximity to the perimeter of said multimembered plate.

1. Apparatus for mounting a work piece on a lathe, which lathe includesa self-centering chuck and chuck jaws, said apparatus comprising incombination: a. a multimembered planar backing plate; b. attachmentmeans for attaching one side of each member of said Plate to one of thechuck jaws; c. lock means for selectively securing adjacent ones of saidmembers in a rigid planar relationship with respect to one another, saidlock means being positioned radially external to the perimeter of thechuck; d. a segmented ring having a plurality of arcuate segments, eachof said segments being anchored to another side of one of said membersto form said segmented ring; and e. receiving means disposed on each ofsaid segments for engaging a portion of the work piece; whereby the workpiece, positioned within said receiving means, is secured to the latheby radially displacing the chuck jaws to draw said receiving meansfirmly against the work piece.
 2. The apparatus as claimed in claim 1,wherein said multimembered planar backing plate comprises threepie-shaped members.
 3. The apparatus as claimed in claim 2, wherein saidlock means comprises a slotted rectangular piece and at least one pairof bolts extending through the slot, each bolt of said pair threadedlyengaging a different one of adjacent ones of said members, whereby ontightening said bolts said adjacent members are rigidly displaced withrespect to one another by said slotted piece.
 4. The apparatus asclaimed in claim 2, wherein said segmented ring comprises threesegments, each one of said segments extending arcuately to either radialedge of the member to which it is attached.
 5. The apparatus as claimedin claim 1, wherein each of said members are non-movably attached to itsrespective chuck jaw by bolts and each of said segments is non-movablyattached to its respective member by bolts.
 6. The apparatus as claimedin claim 3, wherein said lock means is positioned in proximity to theperimeter of said multimembered plate.